This structure provides the following positional adjustments. When the operator turns the adjusting screw 15 clockwise or counterclockwise with the support plate 14 released from the fixed position, the support plate 14 is linearly moved forward or backward relative to the second bracket 13 whereby the fore-aft positional relation between the second bracket 13 and the support plate 14 is adjusted. Further, lateral positional relation between the first bracket 12 and the support plate 14 is adjusted by making adjustment of the fixed position of the second bracket 13 relative to the first bracket 12. Namely, the support plate 14 is mounted to the mounting base 6 stepwise by way of the first bracket 12 and the second bracket 13, and hence the support plate 14 can be positioned at any fore-aft/lateral position based on the mounting base 6 moved up and down along the base 5 by making adjustment of the positional relations with the respective brackets 12, 13. It is noted that a bead feeding direction (to the right as viewed in FIG. 1 and FIG. 3 and to the rear as viewed in FIG. 2) is defined herein as “forward” direction.
The feed lever 23 is formed with a recess 23a at a distal end thereof opposite from a proximal end to which the coupling member 22 is fixed for coupling the swing arm 20 to the feed lever 23. The recess 23a is configured to receive a part of a single bead B as a feed material such that the bead B fed from the storage pipe 30 through the through hole 29a may be directly fed to the sewing position as held in a horizontal position relative to the top surface of the bearing plate 18. The feed lever 23 is configured to be varied in thickness in two steps such that the distal end formed with the recess 23a is thinner than an intermediate portion thereof. Thus, a bottom surface of the feed lever 23 that is opposed to the bearing plate 18 defines different heights from the bearing plate 18, the height changing at the intermediate portion thereof. Since the distal end of the feed lever 23 defines the greater height from the bearing plate 18 than the side with the coupling member 22 fixed thereto, the feed lever 23 can provide space beneath the distal end thereof such as to accommodate a support member 24 independent from the feed lever 23. The support member 24 is configured to have a thickness such that a bottom surface of the support member 24 is flush with the bottom surface of the thicker portion of the feed lever 23.
The support member 24 is forwardly formed with a depressed portion 24a which carries thereon a single bead B fed from the storage pipe 30. In order that the bead B is not carried directly on the bearing plate, the support member 24 (more specifically, the depressed portion 24a) capable of slidable movement along with the feed lever 23 on the bearing plate 18 is adapted to carry thereon the bead B. The support member 24 is further formed with a recess 24b at a distal end of the depressed portion 24a such as to permit the passage of the sewing needle 4. In a state where the bead B is carried on the bearing plate 18 (more specifically, the bead B is held by a pair of clamping claws 25 to be described hereinlater), a bead hole of the carried bead B is aligned with the recess 24b. 
The pair of clamping claws 25 (a clamping section) is disposed on the depressed portion 24a in a manner to be interposed between the feed lever 23 and the depressed portion. For assuredly holding (retaining) the bead B with tips thereof, the paired clamping claws 25 are arranged in a manner to direct the respective claw portions thereof in face-to-face relation, the claw portions being formed in an arc-like shape conforming to an outer periphery of the bead B. These clamping claws 25 are each formed with an engaging hole 25a, and also formed with an engaging groove 25b defined by a corresponding outer peripheral portion thereof recessed toward the engaging hole 25a. A first pin (first member) 26 upstanding from the support member 24 is inserted in the engaging hole 25a of each of the clamping claws 25 so that each clamping claw 25 is supported by the support member 24 in a manner to be rotatable about the engaging hole 25a. Further, the engaging groove 25b of each of the clamping claws 25 is engaged with a second pin (second member) 27 upstanding from the distal end of the feed lever 23. According to the above structure, the support member 24 is not fixedly mounted to the feed lever 23 but is allowed to move back and forth slightly relative to the feed lever 23. For this purpose, the position of the step formed on the bottom of the feed lever 23 and the length of the support member 24 are so decided as to ensure that a clearance is formed between the step on the bottom of the feed lever 23 and a rear end surface of the support member 24 when the feed lever 23 is at the rearmost position.
As described above, the bead feeder conventionally known in the art includes the groove formed in the bearing plate for guiding the bead(s) and the forward and backward movement of the feed lever. One or more of the beads stacked in the storage pipe are once transferred into the groove in the bearing plate, and then are slidably moved on the bearing plate by the feed lever movable in the groove so as to be delivered one by one to the sewing position. Therefore, while delivered by using the feed lever, the bead is subjected to frictional resistance from the bearing plate (specifically, the groove). The frictional resistance fluctuates according to conditions of contact of the delivered bead with individual areas (such as, bottom surface, side surface and the like) of the groove. Hence, the frictional resistance may vary for each bead. If so, the load on the drive motor to operate the feed lever varies according to the magnitude of the frictional resistance on the bead being delivered. Therefore, the load on the drive motor fluctuates on a bead to bead basis.
In this connection, it has been a practice for the conventional bead feeder to require a large motor having such a large drive force as to provide an extra margin, so that the bead can be assuredly delivered to the sewing position even if the bead encounters rather heavy frictional resistance from the individual areas of the groove. In spite of the extra force margin, however, it is not always ensured that a frictional resistance heavier than expected can never be encountered. In the case of such an unexpectedly heavy frictional resistance, the drive motor loses steps, disadvantageously becoming unable to deliver the bead. In the conventional bead feeders, the mechanism for clamping the bead with the paired engaging claws utilizes the spring bias force. If the frictional resistance between the bead and any of the areas of the groove is unduly increased for some reason (for example, the bead is tilted to hit hard against the bottom surface of the groove in the course of delivery), the bead is disengaged from the paired engaging claws spring-biased to clamp the bead therebetween, and hence the bead cannot be delivered. That is, the conventional bead feeders are incapable of proper and stable bead delivery, failing to ensure that the bead is reliably sewn onto the sewing material.